Technical Field
This disclosure relates to a control device that controls two terminating devices virtually directly connected to each other on a network, a communication system including the control device, a control method, and a non-transitory recording medium storing a program for causing a computer to execute the control method.
Related Art
Different segments on a network are connected by relay devices called routers. A broadcast packet to be transmitted to unspecified parties or a multicast packet to be transmitted to specified parties fails to be transmitted from one segment to another segment beyond routers unless the routers are set up for such the transmission.
A technique called tunneling creates a network that virtually directly connects devices to each other with a process of encapsulating packets in accordance with the same protocol or the protocol in a higher layer of the open systems interconnection (OSI) reference model.
The tunneling technique includes “L2 over L3,” which encapsulates a packet in Layer 2 (L2) serving as a data link layer with a packet in Layer 3 (L3) serving as a network layer.
A technique using L2 over L3 encapsulates a packet such as a broadcast packet into a unicast packet to be addressed to a terminal end of a tunnel, and decapsulates the encapsulated packet at the terminal end, to thereby transmit the packet beyond routers to a terminal located downstream of the terminal end in a different segment.